1. Field of the Invention
The present invention relates to an ink-jet recording head and, more particularly, to an ink-jet recording head for generating ink droplets used for a so-called ink-jet recording system.
2. Description of the Prior Art
A conventional ink-jet recording head used for an ink-jet recording system has small ink discharge ports (orifices), an ink path and an ink discharge energy generator arranged in a part of the ink path.
A conventional recording head of this type is, for example, manufactured as follows. A glass or metal substrate is prepared such that small grooves are directly formed in the upper surface by cutting, etching or the like. The substrate can also be prepared by another method whereby a photosensitive resin composition such as a photosensitive resin or a photoresist is applied to a glass or metal substrate and is patterned by photolithography to form the above-mentioned grooves. The resultant substrate is bonded to a glass or metal plate so that the grooves covered with the glass or metal form ink channel. Thereafter, the resultant structure is cut to form ink injection ports, thereby forming a recording head having a desired size.
However, according to such a conventional recording head, it is difficult to uniformly bond the pregrooved substrate and the glass or metal cover, and to bond the cover and an ink channel forming member (to be referred to as a channel member hereinafter) obtained by the photosensitive resin composition. For this reason, an air layer may often be formed at the bonded portion. When the air layer extends in a wide area at the portion subjected to cutting of the recording head, the channel member or the cover severely vibrates, forming cracks or gaps in the surface. Cracks and gaps are also formed in the bonded surface between the substrate and the channel member and between the cover and the channel member, and cause separation. When cracks and gaps are formed in the substrate, ink enters into the substrate and reaches wires connected to an injection energy generating element in the injection energy generator. The wires are than corroded, and in a worst case, the wires are disconnected. When the channel member comprises a photosensitive resin, the adhesion strength thereof can be used to bond the substrate and the cover. For this reason, a special adhesive need not be used and uniform adhesion can be easily accomplished. Although the photosensitive resin has this advantage, the resin contracts while being cured. The contraction stress is concentrated at the cut end face, so that the resin layer is often peeled from the substrate or the cover. In order to prevent such peeling, a thin film of an adhesion accelerator such as a silane coupling agent is formed at the adhesion surface to improve the adhesion strength and prevent peeling. However, this method cannot always provide good results. Another method is also proposed wherein the channel member is eliminated from the cut surface which constitutes the injection ports. In this case, the cover severely vibrates when the head is cut. In the same manner as in the case wherein an air layer is formed in the adhesion portion, cracks and gaps are formed at the cut end face.